Independent circuit

Lethal Dose (2007–2009)

From the beginning of 2007, Toxic and Cyanide would continue to team up and eventually became Lethal Dose. They became a regular attraction at Futureshock, appearing on many shows. The team would have their first title shot at Grand Pro Wrestling's That's Entertainment when they took on WKD for the GPW Tag Team Championship. The team would travel to Real Deal Wrestling where in February and April, had to chances to become the RDW Tag Team Champions but lost both times. They then went to Hull to wrestle for New Generation Wrestling where they won all their matches. With this run of success, they returned to Futureshock at Futureshock #27 and defeated three other teams to become the first FSW Tag Team Champions. However, they would lose the titles to The Doogooders at Futureshock #29. they returned to GPW at Livin' On The Edge to take part in a number one contendership four-way elimination match and lost. For the rest of 2009, they continued to team up but would find little championship success and split up.

Grand Pro Wrestling (2007–2012)

Gallagher, performing as Jack Toxic, made his singles debut at GPW West Park Fun Day and lost to Scarlett Web. Between March and April, Toxic tried to qualify for the Crazy Cruiser 8 2008 but would fail multiple times, however, he won the Last Chance Saloon battle royal and therefore qualified for the tournament. On 2 May, he lost El Ligero in quarter finals. At Justice For All, he defeated Bubblegum in a rumble qualifying match and would go on to be eliminated from the rumble on the same night which was won by Martin Kirby. At Guts & Glory, he returned under the name Jack Gallagher to compete in a four way scrabble match for the GPW British Championship and lost. At Battlefield, he lost a thirty-minute iron man match involving Zack Diamond and Mikey Whiplash for the GPW British Championship, however, next month at Heroes & Villains he defeated Diamond for the title. He would hold the championship until Do Or Die, in December, where he lost it to Ste Mann. Gallagher would introduce his own belt after losing the British Championship, this was akin to the Million Dollar Championship held by Ted DiBiase. He would lose this title, however, at Fireworks to Ste Mann. Following his second loss to Ste Mann, he took a 12-month break from Grand Pro.

Gallagher made his Grand Pro return at the 2013 Crazy Cruiser 8 where he defeated Bubblegum in the Quarter Finals before being pinned by eventual winner El Ligero in the Semi-Finals. At the start of 2014, Gallagher was defeated by CJ Banks at "Back With A Bang". Dissatisfied by this result, Gallagher decided to prove HE was actually the better man and the two developed an intense rivalry. At "Friday Night Thriller 8" in October 2014, Gallagher issued an Open Challenge that was answered by Mike Track, Wahoo Thunderfoot and finally the masked British Bullfrog. During the match it became clear to fans that the "Bullfrog" was actually CJ Banks but fans were stunned when Gallagher managed to pin Banks with a surprise roll-up out of nowhere. Now tied at 1-1, the two met at Final Fight in an 20 Minute "Iron Man" Match. Neither man was able to score a pin fall or submission and the match went to a time limit draw.

The rivalry between Gallagher and Banks continued into 2015 and at Back With A Bang, both men were able to choose their own opponents for the evening. Jack defeated Bubblegum in a rematch from their CC82013 encounter while CJ Banks bested Craig Kollins. With the feud at fever pitch, Grand Pro management decided to settle it at "Saved By The Bell" as they would compete in a match with no time limit. Banks picked up the win to end the feud. Following a loss to Chris Ridgeway at "Cruel Summer", Gallagher took another hiatus from Grand Pro.

The Circus (2015–2016)

Gallagher made his return at Friday Night Thriller 9 where he was revealed to be the fourth member of The Circus alongside "The Ring Master" Nicholas Cartier, Noah and "The IT Girl" Melanie Price. With Gallagher's help, The Circus were able to defeat The Bad Lads and Alex Jones-Casey and enjoyed more success in 2016. Gallagher's final appearance to date took place at the Dom Travis Memorial show, "A Night To Remember" when he defeated former tag team partner, Cyanide.

Futureshock (2006–2016)

On 8 June 2008, Gallagher as Toxic, took part in the Lotto-Thunder Tournament and reached the semi final where he was defeated by Jack Domino. On 13 September, he participated in the FSW Trophy Tournament 2009 and was eliminated in the first round by Sparx. In 2010, he began using the ring name Jack Gallagher. At Futureshock #48, Gallagher won the FSW Trophy Tournament 2010 when he defeated Dave Breaks in the final. On 6 November 2011, Gallagher defeated Dave Rayne to become the FSW Champion. He would hold the championship for fourteen months before losing it to Davey Richards at Futureshock #61. At Futureshock #62, he defeated Stixx and Zack Gibson to become the number one contender for the FSW Championship. Chris Egan announced that Jack Gallagher would be facing Sonjay Dutt at FutureShock #74, but Gallagher instead faced Jay Lethal at FutureShock #74. At the event, Gallagher defeated Dutt by pinfall.

Pro Wrestling Zero1 (2013)

On 3 March 2013, he made his debut for Pro Wrestling Zero1 in Japan, under the ring name Jack Anthony. He joined a tag team match alongside Ikuto Hidaka. On 15 April 2013, Anthony came together with Craig Classic, James Raideen, Jason New, Maybach β, Sebastian Concrete, Steven Walters and Tama Williams to form a gaijinstable named "New Age Wrestling Future" (NWF) under the guidance of Akebono. The stable was shortly afterwards joined by Jonathan Gresham and Mark Coffey.

WWE

Cruiserweight Classic (2016)

Gallagher earned a place in the WWE Cruiserweight Classic by defeating Pete Dunne in a qualifier match at Progress Wrestling's Chapter 29 in April. The tournament began on June 23 with Gallagher defeating Fabian Aichner in his first round match. Gallagher lost to Akira Tozawa in his second round match.

Cruiserweight division (2016–present)

On the 5 September 2016 episode of Raw, Gallagher was announced as part of WWE's upcoming cruiserweight division. On November 29, during the inaugural episode of WWE 205 Live, he defeated Ariya Daivari.